The MotoSport.com Vertex 4-Stroke Piston Kit - Stock Bore includes one of each of the following components with the following attributes: Vertex 4-Stroke Piston Kit: Important Note: This piston is for a stock sized bore. Please measure your cylinder to check clearance before ordering. When it comes to power and performance, Vertex four-stroke pistons are hard to beat. Forged from the highest quality 2618 aluminum alloy, Vertex pistons are perfectly suited to handle the rigors and high pressures of today's modern four-stroke engines. Plus, to aid in the break-in process and reduce wear, every Vertex piston utilizes a unique Molybdenum Disulphide (MOS2) coating on the piston skirt. Vertex Piston includes: Premium quality Vertex piston. Complete set of nitride coated or chrome-plated piston rings. Fully case-hardened wrist pin. Circlips.